Sharp Zaurus (stock ROMs) and compatible found in drivers/usb/net/Kconfig

Help text

Choose this option to support the usb networking links used by
Zaurus models like the SL-5000D, SL-5500, SL-5600, A-300, B-500.
This also supports some related device firmware, as used in some
PDAs from Olympus and some cell phones from Motorola.

If you install an alternate ROM image, such as the Linux 2.6 based
versions of OpenZaurus, you should no longer need to support this
protocol. Only the "eth-fd" or "net_fd" drivers in these devices
really need this non-conformant variant of CDC Ethernet (or in
some cases CDC MDLM) protocol, not "g_ether".